This invention relates generally to the construction of wire fences and more specifically to an improved clamp device for use in stretching fence wire between fence posts.
Typically, existing fence wire stretchers employ a cam member which acts against lug elements projecting from a base plate in order to clamp the wire in place. Such devices have not enjoyed substantial acceptance or success, primarily because the cam members are unduly complex and costly. For example, the camming bar shown in the Combs U.S. Pat. No. 3,881,690 comprises essentially a round bar which has been cut longitudinally in half and welded back together with the halves offset somewhat to achieve a cam configuration. Manifestly, the difficulty involved in fabricating this type of camming bar leads to a high production cost.
Another type of wire stretcher is shown in the Handley U.S. Pat. No. 1,911,274 in which cylindrical clamping sections are arranged eccentrically on a bar in order to produce a camming effect when the bar is turned. Again, the fabrication cost is high due to the difficulty of forming the clamping sections eccentrically on the bar. In addition, since large spaces are presented between the clamping sections, the bar is able to slide axially on the base and thus possibly work loose as it is being used. Accordingly, the device is highly susceptible to slipping along the fence wire as the fence is being strung.
It is an important object of the present invention to provide an improved wire stretching device which may be quickly and easily applied to the fence wire and removed therefrom.
Another object of the invention is to provide a wire stretching device which is able to firmly clamp the fence wire without inadvertently loosening or slipping thereon. In this respect, it is an important feature of the invention that the fingers are able to fit closely in the eccentric grooves so as to prevent the camming bar from possibly slipping along the base plate and thereby working itself loose from the wire.
A further object of the invention is to provide a wire stretching device which is constructed more simply and economically than existing devices.
An additional object of the invention is to provide a wire stretching device in which the pulling force applied by a towing vehicle tends to increase the firmness with which the wire is held.
Still another object of the invention is to provide a wire stretching device which includes an improved guide bar arrangement to prevent twisting and other misalignment.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.